Here is the full list of all 31 Zombie Kill of the Week - there are Reborn achievements.
Get promoted to rank 30.
Go see your friends!
Get 5 meats in a single game from the fridge.
Find the fridge and make it disappear. Repeat 3 times.
Own atleast 5000$ in one match
Kill 15 zombies with a katana, and 25 with saw in one match.
Grill 50 zombies with flame in a single match.
Encounter all 3 tanks, and get them killed.
Slaughter 10 000 zombies in total.
Open all areas in a single match.
Survive 4 minutes in Area 73. (Challenge mode)
Get a shotgun, and make 20 zombies crawl in front of you.
Survive 4 minutes in Homerun. (Challenge mode)
Survive 4 minutes in Arise. (Challenge mode)
Survive 4 minutes in Night At The Mall. (Challenge mode)
Slaughter 5000 zombies in total.
Survive 4 minutes in RedSnow. (Challenge mode)
Get the GiGaGirlGannon, and kill 10 zombies within 10 seconds.
And still going?
Survive 4 minutes in Abandoned Hospital. (Challenge mode)
Fight your way to round 20.
Get yourself killed with a grenade. Dumbass.
Get promoted to rank 10.
Slice 53 zombies in one match.
Kill the zombie bear before he takes your money.
Help your friend in need.
Get 100 headshots in one match.
Zombies are not ment to fly.
You have wasted 5 hours of your life.
You have played ZKW for an hour.
Stand still for 30 seconds, wondering about your life.